-- it's painfully obvious you're not reading what I'm posting, so it's sort of pointless to show that the article doesn't mean what you think it means.

Just concentrate on one piece then - show how

"In the First World War, the average American soldier was still two inches taller than the average German. But sometime around 1955 the situation began to reverse. The Germans and other Europeans went on to grow an extra two centimetres a decade, and some Asian populations several times more, yet Americans haven’t grown taller in fifty years. By now, even the Japanese—once the shortest industrialized people on earth—have nearly caught up with us, and Northern Europeans are three inches taller and rising."

is explained by a reference to late-19th and early-20th-century immigrants to America.